A liquid, colorimetric presence-absence coliphage detection method based on the induction of beta-galactosidase by Escherichia coli is described. The release of beta-galactosidase in the medium due to lytic cell infections by coliphages permits the hydrolysis of a yellow chromogenic substrate that develops into a distinct red coliphage positive sample, while a coliphage negative sample remains ...

Inhibition kinetics of single-beta-galactosidase molecules with the slow-binding inhibitor d-galactal have been characterized by segregating individual enzyme molecules in an array of 50,000 ultra small reaction containers and observing substrate turnover changes with fluorescence microscopy. Inhibited and active states of beta-galactosidase could be clearly distinguished, and the large array s...

Complexes containing plasmid DNA, transferrin-polylysine conjugates, and polylysine-conjugated peptides derived from the N-terminal sequence of the influenza virus hemagglutinin subunit HA-2 have been used for the transfer of luciferase or beta-galactosidase marker genes to K562 cells, HeLa cells, and BNL CL.2 hepatocytes. These DNA complexes mimic the entry of viruses into cells, as they conta...

A new method for the enumeration of lymphoid cells with specific surface-receptors for antigen is described, based on the use of beta-D-galactosidase (EC 3.2.1.23), either directly as an antigen or as a conjugated antigen. Binding of beta-D-galactosidase is revealed by its activity in releasing riboflavin from a synthetic substrate, riboflavin-beta-D-galactopyranoside. The riboflavin, inactive ...

The fusion reaction mediated by viral envelope glycoproteins proceeds through an ordered series of conformational changes in the envelope glycoprotein. Fusion inhibitors have been developed that target glycoprotein subunits, arresting the reaction at different points in the process. We report the development of a novel method for detecting viral glycoprotein-mediated fusion that is based on the...

Introduction: It has been reported the alkaline response of pancreas to duodenal acidification is partly mediated through duodenal release of H2S, but till now the effect of duodenal acidification on gastric H2S release has not been investigated. Therefore, the present study designed to evaluate the effects of duodenal acidification on gastric H2S release and level of mRNA expression of cys...

The common food additive carrageenan (CGN) predictably induces intestinal inflammation in animal models. Mechanisms of CGN-induced nuclear factor κB and interleukin-8 (IL-8) stimulation include an immune-mediated pathway involving toll-like receptor 4 (TLR4) and B-cell lymphoma/leukemia 10 (BCL10) and a reactive oxygen species (ROS)-mediated pathway. To determine how the structure of CGN contri...

The beta-galactosidase activities arising from Tn5lac insertions in several genes required for antibiotic TA production were measured under different growth conditions. In all of the non-TA-producing mutants, the beta-galactosidase specific activity was higher when the cells were grown in nutrient-limited 0.5CTS medium (0.5% Casitone plus alanine, serine, and glucose) than in rich 2CT medium (2...